ABSTRACT
The introduction of pulse oximetry in clinical practice has allowed for simple and non-invasive measurement of arterial oxygen saturation. However, theoretical principles are not always well known and well understood by health care professionals. They must know factors that affect measurements, like motion artifacts poor perfusion being the most important. The calculation of the percentage of arterial oxyhemoglobin is based on the distinct characteristics of light absorption in the red and infrared spectra by oxygenated versus deoxygenated hemoglobin. Now they are new technologies to minimize measuremet errors, thus contributing to an appropriate clinical decision making.
La introducción de la oximetría de pulso en la práctica clínica ha permitido medir en forma sencilla y no invasiva la saturación arterial de oxígeno. Sin embargo, los principios teóricos no siempre son bien conocidos ni bien comprendidos por los profesionales de la salud. Deben conocer los factores que afectan a las mediciones, como artefactos de movimiento y mala perfusión, siendo los más importantes. El cálculo del porcentaje de oxihemoglobina arterial se basa en las características distintivas de absorción de luz en el espectro rojo e infrarrojos por parte de la hemoglobina oxigenada frente a la desoxigenada. Actualmente existen nuevas tecnologías para reducir al mínimo los errores de medición, lo que contribuye a una adecuada toma de decisiones clínicas.
Subject(s)
Humans , Child , Hypoxia/diagnosis , Oximetry/instrumentation , Oximetry/methodsABSTRACT
A exposição aguda à altitude sem aclimatação prévia pode provocar mal-estar e diminuir o desempenho físico e esportivo. O objetivo deste estudo foi verificar o efeito de sessões de hipoxia normobárica, em repouso, na Frequência Cardíaca (FC) e Saturação de Oxigênio da Hemoglobina (SpO2) em atletas de futebol profissional. Participaram do estudo 13 atletas, os quais foram submetidos a 15 sessões de hipoxia, 5-6 vezes por semana. A duração das sessões foi de 60 min, com fração inspirada de oxigênio entre 14% e 12 %. A SpO2 e FC foram registrados segundo a segundo durante a primeira e última sessão. Para comparar, a SpO2 e FC da primeira sessão, última sessão e normoxia foi utilizado Anova para medidas repetidas. Houve aumento da SpO2 (p<0,05) e redução da FC (p<0,05) na última sessão, quando comparado à primeira. Concluímos que o protocolo de treinamento utilizado no estudo melhora a resposta do organismo em hipoxia.
The acute exposure at altitude without previous acclimatization may cause sickness and decrease the sport and physical performance. This research aimed at verifying the effect of normobaric hypoxia sessions, at rest, on the Hemoglobin Oxygen Saturation (SpO2) and the Heart Rate (HR) of professional soccer athletes. Thirteen athletes performed 15 sessions of hypoxia, 5-6 times a week, with 60 min of duration and with the fraction of inspired oxygen between 14 and 12%. The SpO2 and HR were recorded every second during the first and the last session. In order to compare the SpO2 and HR from the first session, last session and normoxia it was used the ANOVA with repeated measures. There was an increase in the SpO2 (p<0.05) and a decreased HR (p<0.05) for the last session when compared to the first session. We conclude that the training protocol used in the acclimatization study improves the organism response to hypoxia.
ABSTRACT
BACKGROUND: In neonates and infants with congenital cyanotic heart disease, venous blood, rich in CO2 and poor in O2, is mixed with pulmonary venous blood at left heart. As a consequence, any given degree of decreases in SpO2 is accompanied by obligatory increase in PaCO2 - PETCO2 difference. This study was designed to evaluate these relationship in 20 pediatric patients. METHODS: After endotracheal intubation with high dose fentanyl and pancuroniun, PETCO2 was measured by capnometer (side stream, sample gas flow rate of 200 ml/min; sampling site at elbow connector area) and SpO2 probe was attached at toe or finger. Observations were made 4 or 5 times before initiation of CPB. Ventilation was controlled by pressure type ventilator, partial rebreathing circuit at frequency of 25-35 breaths/min, an inspiratory time of 25% with an end-inspiratory pause of 10%, and peak airway pressure of 20 +/- 2 cmH2O. RESULT : Mean values of PaCO2 - PETCO2 difference were increased linely with decreases in SpO2. The regression equation is mean (PaCO2 - PETCO2) (mmHg) = 23.9 0.22 mean SpO2 (r= 0.51, p=0.028) CONCLUSIONS: The relationship between PaCO2 - PETCO2 was found to agree with that predicted by theory confirming that in congenital cyanotic heart patients, PaCO2 increases by 2-5 mmHg for every 10% reduction in SpO2. This relationship may be useful when attemping to estimate PaCO2 from PETCO2 in the management of congenital cyanotic heart patients.